Thermoelectric control for heaters



ug. 8, lgsl. I H, 1 PlATT 1,819,620

THERMOELECTRIC CONTRQL FOR HEATERS Filed Aug. f 1925 Patented Aug. 18, 1931 STATES PATENT OFFICE HOWARD I. PIATT, OF LANSING, MICHIGAN, ASSIGNOR TO MOTOR WHEEL CORPORA- TION, OF LANSING, MICHIGAN, A CORPORATION F MICHIGAN THERMOELECTRIC CONTROI.; FORYHEATERS Application led August 13, 1928. Serial No. 299,150.

This invention relates to thermoelectric control for heaters and it has among its objects the' provision of an improved thermostatic fuel feed control in heaters utilizing fluid fuel, although in its broad aspects the invention 'is not restricted to a particular type of fuel feed systems.

The invention will be best understood from the following description of an exemplitication thereof, reference being had to the accompanying drawings, wherein Fig. 1 is a diagrammatic view illustrating a heater system embodying the invention; and

Fig. 2 is a sectional View of the fuel control valve of Fig. 1.

' The present invention is designed for operation in heater systems such as described in my co-pending application, Serial No. 237,957 (case No. 7 092) filed December 5, 1927, but it is also useful in other systems and other applications. Such heater system is shown in Fig. 1, and` includes, in general, a water boiler or heater 1 in which water is heated by means of an oil burner 2 to which fuel is supplied from a fuel feed line 3 leading from a main oil reservoir not shown in the drawings. A head control chamber 4 is interposed in the fuel feed line so as to maintain a constant level and pressure head of the fuel flowing to the burner. The heated water from the boiler is circulated by means of a suitable pipe system 5 through a heating apparatus such as radiators 6 disposed in the spaces that are to be heated, ,a dottedline rectangle 7 being intended to indicate the heated space such as a room or ahouse located remotely or spaced from the heater 1.

In my last identified-application there is described a fuel feed control system including two valves disposed in the fuel line leading to the burner, one valve beingresponsive to the local conditions in the heater to regulate the fuel'low so as to maintain the temperature of the boiler water or the heating medium withi'n a predetermined range, while ,the other valve is remotely controlled from the' room that is to be heated so as to maintain the temperature of said room at a predeterminedly adjustable value.

According to the present invention I secure the double control of the fuel feed to the burner 4by the local temperature of the heating medium and by the remote temperature of the heated space by means of a single valve 11 illustrated in detail in Fig. 2. The valve comprises a valve casing 12 having a main valve chamber 13 provided with an inlet port 14 and an outlet port 15 to which the fuel feed line 3 is connected. Within the valve ehanr ber 13 is mounted a needle valve 16 such as described in my last mentioned application. The stem of theneedle valve 16 has a collar 17 by means of which the valve may be lifted to open the fuel flow from the inlet port to the outlet port, or moved downwardly and released to reduce or stop the fuel flow.

The valve casing 12 is provided with a lateral extension 20 having at its end threaded section 21 by means of which may be threaded into a ange 22 at an open` ing in the valve of the heater 1. The open end of the valve extension 2O is closed by a. thermostat casing in the form of a short pipe. 23 having one end o en and communicating with the interior o the extension 20, and another end closed by a removable threaded plug 24. The inner side of the plug 24 has a projection 25 to which is secured one end of a bimetallic `strip 26. constituting the thermostat element of the valve. The other free end of the bimetallic strip 26 has secured thereto an extension arm 27 which engages the collar 17 so as to transmit the upward and downward movement of the bimetallic strip 26 to the stem of they needle valve 16, thereby controlling the opening thereof. Adjacent and preferably surrounding the free end of. the thermostatstrip 26 within the thermostat chamber formed in the casing 23 there is also mounted a heating element in the form of a heating coil 31 to which current may be supplied by means of leads 32 extending through the walls of the valve casing. The leads 32 are so secured in the wall casing as to prevent leakage of oil. This may be effected by molding the lead wires into a suitable insulating plug 33 of a ma terial such as hekelite, end securing the plug Within a perforation in the casing 20. Any other suitable construction may he adopted and, if desired, one et the leeds may grounded to the casing and connection there to established through Contact with the eesing. l

A partition or hottie 3d is inserted Within the opening in the extension 20 so es to seperete the chaniher surrounding the thermostat 26 from the part of the'valve cheminer which oil is flowing to the outiet port. this Way more uniform temperature conditions, unaffected by changes in tempereture of the oil flowing through the valve casing will he maintained adjacent the therinost strip 26. The hottie is provided with e suitehie slot to permit free and unobstructed movement of the extension arm 2? to cios'e and open the valve i6.

The extension oie the casing 20 is so errenged that the chmnher surrounding the hirnetsilic strip 26 is disposed outside o'f the path o the dow of the `duid fuel from the inlet port to the outlet port. lin this wey the hody o' oil which fills the entire space coniinuniceting with the interior of the unive chamber 13 will remain stationary in the proximity ot the thermostat strip 26 end here the temperature of the surrounding spese.

As seen in the drawings, the thermostat casing 23 projects into the interior o' Ylooiler 1 and the Walls of that portion of the thermostat casing are directly exposed the .heating medium. Accordingly, the ternperature of the medium `will he readily cornmunicated through the Wells oit the thermostat casing und the plug 24C to the adjacent portion of the himetelic strip 26, thereby controlling the deflection of the letter end there through the position ot the needle relive lo. lf the temperature ot the water in the hoiler l rises above e predetermined 'velue es determined hy the characteristics sind seta ting ot the hirnetsllic strip 26, the strip Wilt turn downwardly reducing,` the velue opening and cutting down the fuel dow so es to reduce 'the heat generated hy the burner.,

@n the other hand., ithe Writer tempereture tends to drop below the predetermined velue, the himetellc strip will curl upwsrdly to open the valve und increase the Enel tion., @n this control action ot' the veli/'e hy temperature conditions of the Waiter constituting the heating medium in the looiier there is superposed en additional `control hf; the temperature in the room that is heeted by the heating medium.. This second con trol is elected hy mee-ns of the eoremen tioned heater coil 3l the two leeds 32 ot which are arranged to he energized *from e suitnhle supply source, such as e battery 35, hy n remote control instrument 36 disposed in the room the temperature ot which is to he controlled. 'lhe remote control instrument 36 ESSE@ may he of any desired type end arranged to either continuously or stepwise Very the heeting current supplied to the heating coii 3i so es to exercise on the thermostat strip 26 en edditionni remote control action determined sired loe ninintnined. 1- inner end of the soi i 3?' is connecte@` Jo e rotatably mounted sn ntry/ing en actuating hy ineens of t ch a switch el muy he thrown either to the right or the lef" to control the energizetion ot the heater cor;` 3i of T e tuoi.

votre. .r or any predetermined setting' or c the clsrnning member 38 of the room thermostelt 3d rise oif the temperature shove the desired veine will cause the spire thror:7 the switch tothe left? l i ing circuit for "i e heater co l sutlicient cierren the co proximity of ene end or strin 2@ so muehheet conse the strip 26 to downwardly f entirely close the votre lo, therehy interrupting the 'luel iiow te the burner., the temperature in the room drops helen* the desired value the spiral t? will throw the switch eil to the right opening the energizing circuit of the heater coil nlhis reduces the temperature 1n the neighborhood or the veive thermostat 26 and restores its control notion hy the temperature oil the 'nesting medium in the boiler adjacent the submerged end oit the thermostat casing 23,

the foregoing arrangement ll here thus e doel-ole control notion ot the opening of the telve, s loeel or hesic action by the temperature of the heating medium which ectsncontinuously end produces n continuous regulation oi? the vulve opening und of the `fuel tion end e secondary or super-posed control notion hy the tempereture of the roorn to he hee The letter action is stepwise end either 'produces closure of the velue, cutting;

ont the continuous regulating; notion oie the medium snrronnding; the ixed portion of tue telve thermosten or restores the regueting action of seid mediinnu The temperature ranges of the loczrl reguleting notion of the hostingv medium und et the remote control notion or the room thermostat 1% so chosen thet, under no conditions., cen the hoiler temperature exceed menirnurn velue that might he dangerous to the heitera With this in View, the valve thermostat strip 26 has such characteristiscs and is so set that it prevents fuel flow yto the hnrner ii the temperature ot' the heating mediurn within the heater exceeds a predetermined maximum safe value. This maximum value of the heating medium is so chosen with relation to the range of the temperatures desired to be maintained in the room 7 that is to be heated as to permit heatin of the room by the circulating hea-ting me lum to a temperature that is at least equal to the maximum temperature that is desired to be maintained in the room. It is the function of the room thermostat 36 to maintain in the room any desired lower temperature by intermittent for, if desired, continuous, additional control of the fuel flow so as to maintain the room temperature at the desired value below its maximum as determined by the maximum temperature of the heating medium.

The invention is not limited to the details of construction and arrangements described and illustrated hereinabove, but many modifications thereof will suggest themselves to i those skilled in the art. It is accordingly desired that the appended claims be given a broad construction commensurate with the scope of the invention within the art.

I claim:

1. In a fluid fuel heater control system, a valve, a thermostatic element exposed to surroundings the temperature of which is Ato be controlled, a mechanical operating connection between the thermostatic element and the valve, and means for electrically ,super-imposing upon the thermostatic element an additional temperature variation independent of the temperature of the surroundings thereof.

2. In a fluid fuel heater control system, a fluid flow control valve, a thermostatic element exposed to the temperature within the heater which is to be controlled, a mechanical operating connection between the thermostatic element and the valve for opening and closing the `same by the action of the thermostatic element, means for electrically generating in proximity of said thermostatic element heat; to exercise thereon a control ac-y ture thereof, a valve member in said valve casing for controlling the fuel flowtherethrough, a thermostat in said-thermostat casing actuated for mechanical movement by the temperature of the surroundings thereof,

' a mechanical operating connection between the thermostat and valve for controlling the movement of said valve member in response to the movement of said thermostat, and electrical means for generating in proximity to said thermostat heat independently of the temperature of the heated space surrounding said thermostat casing.

4. The combination with a fuel fluid heater having a heated space, a fuel feed valve comprising a valve casing having an inlet and utlet'port, a valve member movable in said casing for closing and opening the f uel flow, a thermostat casing;` communicating with said valve casing, said thermostat casing projecting int-o the heated space of said heater, a thermostat element in said thermostat casing, a mechanical connection between said thermostat and said valve member for controlling the opening of said valve in response to the movement of said thermostat element, an electrical heater element associated with said thermostat element for varying the temperature thereof independently of the temperature of the surrounding space, and control means for said heater element responsive to the temperature of surroundings remote from the heater.

5. The combination with a fluid fuel heater having a heated space, a fuel feed valve comprising a valve casing having an inlet and outlet port, a valve member movable in said casing for closing and opening the fuel flow, a thermostat casing communicating with said valve casing, said thermostat casingr projecting into the heated space of said heater, a

lthermostat elementin said thermostat casing, a mechanical connection between said thermostat and sald valve member for controlling the opening of sald valve 1n response to the movement of said thermostat element` an electrical heater element associated with said thermostat element for varying the telnperature thereof independently of the temperature of the surrounding space. and a remotely disposed thermostat for controlling 1 the energization of said heater element.

6. The combination with a fluid fuel heatel having a heated space, of a fuel control valve having a valve casing and a valve member movable between open and closed position in said valve casing for controlhng the fuel and a remotely positioned thermostat responsive to temperature conditions distinct `from the heated space of said heater for controlling the electric heater and causing said .valve member to move to closed position in response to a predetermined temperature ical oper eing connection between. therthermomostatic ement and the valve, an a tnermostat disposed in a space remote om said thermostatic element for superimposing on the latter an additional temperature variation independent et the temperature ci' the surroundings. i

9. a duid fuel control system, inici flow control valve, a thermostatic eiem posed surroundings the temperature of which is to he controlled, a mechanical operating connection between the thermostatic element and the valve for opening and closing the same loy the action of the thermostatic element, a second thermostat disposed in a space remote from said first mentioned thermostatic element, and' means controlled by said second thermostat Jfor generating in proximity to said first thermostatic element heat to exercise thereon a control action supplemental to the control action of the surroundings.

10. ln a iluid fuel control system, a fluid fuel control valve, a first thermostatic element exposed to surroundings the temperature oi which is to be controlled, an operating connection between said iirst thermostatic element and said valve for operating the latter, a second thermostatic element, and means for generating heat in proximity to said thermostatic element in response to the action oil said second thermostatic clement.,

il. a duid fuel control system, a fuel valve, a thermostat element for continuously controlling the action of said valve to maintain predetermined temperature conditions, and a supplemental heating element adjacent said thermostat for varying the range of the continuous control action of said thermostat clement. A

l2. lin a fluid 'fuel control system, a valve', a thermostat element exposed to surroundings the temperature of which is to be controlled, an operating connection between said thermostat element and the valve for controlling the opening thereof to vary the fuel supply in response to the temperature adjacent to said thermostat, and remotely controlled means for generating heat adjacent temperature range, an operating conne n to saidthermostat element to vary the range 'of the regulating action of said thermostat. i3., ln a duid fuel control system, a valve, a thermostat disposed adjacent to said valve and exposed to surroundings the temperat re l of which is to be controlled for exercising a controlling action over a predetermiT ed between saidA thermostat and said` ya wry the fuel tion! 'for maintaining predeltmmined temperature conditions in ronndings of siiid thermostat, the aetior said thermostat tending to maintain. perature determined solely by the ci 'I istics oi? said thermostat-aand means tor fre e heat adjacent to said thermosta i endentiy of the surrounding tempera 4shitting the regulating action of saA mostat 'to a different temperature r in a fluid fuel control system, a heater having a heated space, a 'i valve for said heater comprising valve casing, avalve member mounted in said valve casing for controlling the iuel flow in said heater, a thermostat casing communicating with said valve casing, said thermostat casing being exposed to the heated space of said heater, a thermostat element in said thermostat casing, a'mechanical connection between said thermostat element and said Valve to cause continuous regulation of the opening thereof for maintaininga predetermined temperature in the heated space of said heater, the regulating action ot said thermostat clement depending on its natural characteristics and being arranged to maintain a predetermined temperature, and means for supplementally electrically heating the space adjacent to said thermostat element to vary thc range ot its continuous regulating action.

l5. ln a fluid feed valve control mechanisin, a valve casing having an inlet and outlet, a Valve in the casing movable to open and 'closed position to control the How of iuid. a loi-metallic thermostat disposed Within the valve casing, a mechanical connection between the thermostat and valve to move 'the valve in response to action of thermostat, an electric heater within valve casing arranged to vary the operating range of the thermostat.

lo. 'l'nfa heater system, fuel toed means, iii-metallic'thermostat connected to said iced means tocontrol the How of fuel in said heater system, electrical heating means adjacent said thermostat Jfor controlling the operating range of the thermostat, a second remotely positioned thermostat for controlling-the generation ot heat in said electrical heating means, and additional means for intermittently producing heat in said electrical heating means in response to variation of the second thermostat.K

17. Apparatus of the class described comprising in combination a temperature reias sponsive element, a portion of said element being subjected to a medium the temperature of Which is to be controlled, and temperature i responsive means controlling the temperature of another portion of said element and responsive to another temperature to be controlled.

18. Apparatus of the class described comprising in combination a temperature responsive element, means for subjecting said element to a temperature to be controlled, and independently acting temperature controlling means acting on said element.

19. Apparatus of the class described comprising in combination a temperature responsive element, a portion of said element being subjected to a medium the temperature of which is to be controlled, and heating means acting on another portion of said element and controlled by means subjected to a second medium Whose temperature is to be controlled.

20. Apparatus of the class described comprising in combination a temperature responsive element, a portion of said element being subjected to a medium the temperature of which is to be controlled, and heating` `means surrounding another portion of said element and actuated by the rise and fall of a second temperature to be controlled.

21. A heating system comprising a heater, a thermostat, a portion of said thermostat being subjected to the temperature Within said heater, an electric heating element adjacent another portion of said thermostat, thermostatic switch means in circuit with said heating element, said means being subjected to a temperature Without said heater, and means operated by said thermostat for controlling said heater.

22. In a fluid heater control system, a bimetallic temperature responsive element, means for subjecting the said element to a temperature to be controlled, and independent heating means acting on said element, said first-mentioned means and the heating means being relatively more directly effective on separate portions of the bi-metallic element.

23. In a heater control system, a bi-metallic temperature responsive element subjected to a medium the'temperature of which -is to be controlled, and heating means acting on a portion of said bi-metallic element and controlled by means subjected to a second medium Whose temperature is to be controlled, said heating means and first-mentioned medium acting respectively moredirectly on separate portions of the bi-metallic element.

In testimony whereof I have hereunto subscribed my name.

HOWARD I. PIATT. 

